Background: Flaxseed has been studied for various health benefits in humans, including prostate health, glucose control, and cardiovascular health. Cholesterol levels and high blood pressure are known to be risk factors for cardiovascular disease. Whole flaxseed has had variable effects on serum lipid levels, perhaps a consequence of variations in the amounts of secoisolariciresinol diglucoside (SDG) found in different flax cultivars, making the study of this bioactive compound difficult.